发明名称 |
Imaging lens, camera, and portable information terminal device |
摘要 |
An imaging lens, includes: in order from an object side to an image side, a first negative lens group including a negative lens a concave surface of which faces the image side; a second positive lens group including a negative lens a concave surface of which faces the object side, and a positive lens, or a cemented lens entirely having a positive refractive power in order from the object side to the image side; an aperture; a third positive lens group including a cemented lens of a biconvex lens and a biconcave lens from the object side; and a fourth lens group having a weakest refractive power among all of the lens groups and including a single lens, or a cemented lens, a surface on the object side of which is concave and a surface on the image side of which is convex. |
申请公布号 |
US9134507(B2) |
申请公布日期 |
2015.09.15 |
申请号 |
US201313906594 |
申请日期 |
2013.05.31 |
申请人 |
RICOH COMPANY, LTD. |
发明人 |
Ohashi Kazuyasu |
分类号 |
G02B9/34;G02B13/00;G02B9/60;G02B13/04 |
主分类号 |
G02B9/34 |
代理机构 |
Oblon, McClelland, Maier & Neustadt, L.L.P. |
代理人 |
Oblon, McClelland, Maier & Neustadt, L.L.P. |
主权项 |
1. An imaging lens, consisting of in order from an object side to an image side,
a first lens group having a negative refractive power; a second lens group having a positive refractive power; an aperture; a third lens group having a positive refractive power; and a fourth lens group, wherein a refractive power of the fourth lens group is weakest among all of the lens groups, the first lens group consists of a negative lens a concave surface of which faces the image side, the second lens group consists of in order from the object side to the image side a negative lens a concave surface of which faces the object side, and a positive lens, or a cemented lens entirely having a positive refractive power, the third lens group consists of a cemented lens of a biconvex lens and a biconcave lens from the object side, and the fourth lens group is a single lens, or a cemented lens, a surface on the object side of which is a concave surface and a surface on the image side of which is a convex surface. |
地址 |
Tokyo JP |